A typical acoustic guitar has a hollow body or sound box connected to a neck. The hollow body has a soundboard with a sound hole, a back or bottom board spaced from the soundboard, and a shaped side wall which connects between the soundboard and backboard.
The acoustic guitar has a series of strings strung at substantial tension from a bridge on the soundboard, across a portion of the soundboard, and along the neck. The string tension creates forces which act on the neck and the soundboard and which, over time, can cause bending, cracking or other damage. The damage can result in structural failure and altered intonation of the acoustic guitar. Methods of compensating for these factors have been employed in the past.
Traditionally, necks of stringed instruments have been made of wood. Wooden necks, however, tend to bend and warp under the load imposed on them by the tension of the strings, due to exposure to temperature or humidity variations, or due to aggressive playing styles. In attempts to alleviate these inherent problems, prior art wooden neck constructions have incorporated truss rods, or other additional structural elements, within the neck to bear some of the load exerted on the neck by the strings. Prior art neck constructions have also incorporated separate adjustment mechanisms to correct any warping or bending which has already occurred.
One such prior art neck construction is shown in U.S. Pat. No. 5,018,423. This patent discloses a neck construction which includes a metal rod within a wooden neck which extends from the base of the peg head to the body of the stringed instrument. This rod functions as a truss rod for adjusting the vertical space between the strings and the neck, or, in other words, for adjusting the position of the fingerboard and the neck structure relative to the plane of the strings (otherwise known as relief adjustment) to suit user preferences. The rod also functions as a structural element which bears most of the load exerted on the neck by the strings. The neck structure also includes an additional device for rotatably adjusting the neck to compensate for any bending or warping which may occur.
Neck compositions of this type do reduce stress induced deformation of the wooden neck, but are limited in their effectiveness. Any neck in which wood is a structural element will inevitably undergo a certain amount of deformation, be it due to string tension, humidity, temperature, or aggressive use. Devices such as that shown in U.S. Pat. No. 5,018,423 can only counteract and/or correct such deformations. Furthermore, since the rod serves as the relief adjustment mechanism as well as the primary load bearing element, its ability to make and maintain fine adjustments is limited.
Another prior art device which has used a structural reinforcement in a wooden neck is U.S. Pat. No. 4,304,277. This device provides two opposing reinforcing members separated by a spacer. Grip members are attached to each of the reinforcing members for the purpose of giving the instrument the physical look and feel of an instrument with a wooden neck. The reinforcing members, the spacer, and the grip members all cooperate to bear the load of the string tension. As with the device shown in U.S. Pat. No. 5,018,423, however, the grip members and spacer are structural members which will inevitably undergo deformation if made of wood.
Other prior art neck constructions have addressed the problems of warping and bending associated with wooden necks by replacing the wooden neck with a neck made of a composite material. For example, U.S. Pat. No. 4,846,039 discloses a solid single piece neck construction made of layers of epoxy resin and powdered carbon mixture, with longitudinally laid carbon fibers. A neck made of this material does not bend or warp, and is of sufficient strength to withstand the string tension without deforming, and without the need for additional structural reinforcement.
A significant disadvantage of composite necks, however, is that they have significantly different tonal properties than wooden necks. To many users who prefer the response and tonal coloration associated with traditional wooden necks, composite necks are unacceptable.
One prior art device disclosed in U.S. Pat. No. 4,121,492 has combined a forged aluminum reinforcing member with wooden or plastic inserts with the object of preserving the “desirable feel and appearance of wood or plastic materials”. (Col. 1, lines 56-62).
Further prior art include U.S. Pat. No. 5,990,396, U.S. Pat. No. 6,111,175, U.S. Pat. No. 6,017,65, U.S. Pat. No. 4,877,070, U.S. Pat. No. 4,846,039, U.S. Pat. No. 4,681,009 and U.S. Pat. No. 6,100,458.
All US patents and applications all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention in any way, the invention is briefly summarized in some of its aspects below.